Avaya Partner 18D Series 2 Telephone 2-line x 24 character back-lit display The Partner 18D Series 2 telephone is compatible with Partner, Partner Plus, Partner II, or Partner ACS Also compatible with IP Office Quick Version or Basic Edition equipped with IP500 ETR 6 Base Card Built-in conference, transfer, hold, and speaker buttons Hands-free answer on intercom (HFAI)